3 research outputs found
Formulations for analysis of Probe-Fed printed antennas in SuperNEC
Formulations for analysis of printed antenna structures are derived and compared, to determine one to
implemented in SuperNEC based on the efficiency of its numerical solution in terms of memory usage and
solution time. SuperNEC is a software application for computing the response of electromagnetic structures
to electromagnetic fields. SuperNEC cannot be used for simulation of printed antenna structures. This is
because the formulation that is implemented in SuperNEC does not account for the effect of the substrates
that the radiating elements of the antenna structure are printed on, and it is also not intended for antenna
structures whose radiating elements are surfaces. Two MoM (Method of Moments) formulations and a FEM
(Finite Element Method)-MoM formulation are presented, together with different models for the antenna
feed. The FEM-MoM formulation is selected for implementation in SuperNEC because it is argued that it
is likely to be more memory efficient when compared to the MoM formulations, and also that less time
is required to fill the matrices resulting from the numerical solution of the formulation. The formulation
is implemented in a stand alone software application, which will be integrated into SuperNEC. Numerical
results that are computed using the software application are presented to illustrate correct implementation of
the formulation. The results are compared to: an exact solution, results from another publication, and results
computed using a different formulation. Good agreement is obtained in each case
Brushless doubly fed machine magnetic field distribution characteristics and their impact on the analysis and design
This paper contributes to the characterisation of the brushless doubly fed induction generator (BDFIG), which is attractive as a variable speed generator in applications (offshore wind turbine) with minimum maintenance requirements. The BDFIG has two three-phase stator windings of different pole numbers housed within the same stator slots and a shortcircuited rotor winding capable of coupling fields of different pole numbers. The stator windings and rotor winding create a magnetic field distribution with a range of characteristics different to those of conventional induction generators. This paper presents an analysis to identify the field characteristics and discusses their impact on the analysis and design of the BDFIG. The characteristics are determined from an analysis of the sum of two rotating sinusoidal field waveforms and confirmed by comparison with time-stepping finite element results and measured magnetic flux density data